At present the energy consumed by mobile network operators consists largely in the consumption of energy in the radio network. Attempting to reduce energy consumption from the radio network e.g. increased power efficiency in the operation of 2G and 3G RAN infrastructure—a crucial component part of the system—will lead to significant savings. Drivers are not only to reduce operating costs but also in turn to reduce carbon emissions due to the wasted energy.
In 2G networks, due to the TDMA structure of the GERAN technology it has been possible to find relatively efficient solutions allowing to switch-off TRX's whenever there is no traffic either on a short term basis (switch off in given timeslots) or on a long term basis (full TRX switch-off when no traffic). This is especially efficient because legacy 2G RF hardware is traditionally based on single carrier power amplifier, hence when switching-off a TRX, the power amplifier can be completely switched-off.
In 3G networks, due to the CDMA structure of the UMTS technology even when there is no voice or data traffic to be carried over a given carrier, the common channels are still transmitted continuously which prevents to perform any switch-off of the power amplifier. Only when there is more than one carrier active at the same time it is possible to switch-off the extra carriers (one carrier still being transmitted to keep the network operational and allow waking-up the dormant cells when required). In addition, the common use of multicarrier makes this switch-off of extra carriers still quite inefficient as it is not possible to fully switch-off the power amplifier. Hence the continuous transmission in 3G makes the Node B's consume significant amount of power even when there is no or relatively low traffic. The present invention provides a solution for the commented problem.
It is well-known that abbreviations and acronyms are frequently used in the mobile telephony field. Below is a glossary of acronyms/terms used throughout the present specification:    BCH Broadcast Channel    CDMA Code Division Multiple Access    CN Core Network    CPICH Common Pilot Channel    DCH Dedicated Channel    DL Downlink    DRX Discontinuous Reception    FACH Forward Access Channel    GERAN GSM EDGE Radio Access Network    KA Keep-Alive    P-CCPCH Primary Common Control Physical Channel    P-CPICH Primary Common Pilot Channel    PCH Paging Channel    RACH Random Access Channel    RAN Radio Access Network    RNC Radio Network Controller    RSCP Received Signal Code Power    SCH Synchronization Channel    SIB System Information Block    TRX Transceiver    UE User Equipment    UL Uplink    UMTS Universal Mobile Telecommunications System    UTRAN UMTS Terrestrial Radio Access Network    WCDMA Wideband Code Division Multiple Access